Ambitious GM rice project enters next phase

Rhiannon Smith, Scidev.net, July 1, 2010

An international consortium aiming to re-engineer rice to increase yields by 50 per cent is about to move into the second phase of its decades-long project. The project aims to genetically modify rice to use a more efficient method of photosynthesis — the process by which plants convert carbon dioxide into carbohydrates needed for growth.  

Rice has a type of photosynthesis called C3. But some plants, including maize and sorghum, have evolved to use a type called C4. The C4 crops are anatomically different from C3s and are better at concentrating carbon dioxide around a particular enzyme — RuBisCO — which is crucial in photosynthesis.

If the scientists are successful in creating rice that follows the C4 pathway the crop could produce 50 per cent more grain, and would require less water and fertiliser.

The C4 plants work best in hot climates, so could be important as global warming increases. "As temperatures rise, C4 plants will photosynthesise better than C3s," said Richard Leegood, a plant biologist from the UK-based University of Sheffield, which is leading an international team of researchers, coordinated by the International Rice Research Institute (IRRI) in the Philippines.

The project received US$11.1 million of funding over three years from the Bill and Melinda Gates Foundation in October 2008. Most of this money has gone to IRRI, said Leegood, where researchers are doing the mammoth task of screening plants to try to identify the genes that control photosynthesis.

The project is a long-term venture — Leegood says that it will be at least 20 years before the modified rice is available. "Many genes need to be manipulated, then engineered traits need to be transferred into commercial varieties."

Since C3 photosynthesis evolved naturally into the C4 type in other plants more than 60 times through history, Leegood hopes that the public will accept this GM rice. "It is not an unnatural process; it's something that plants do ordinarily."

Lewis Ziska, a plant physiologist at the US Department of Agriculture said: "This kind of innovative work is crucial if we are going to meet the demands of an expanding population".. Although there are many other issues that cause food insecurity, Leegood said that this solution could tackle those limitations that are "inherent" in the production of such crops. The Sheffield work forms part of its Project Sunshine, a programme that investigates how the power of the sun can be harnessed to meet the world's increasing food and energy needs.